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Subject[PATCH 2/2] dma-debug: Put all hash-chain locks into the same lock class
Date
From: Ingo Molnar <mingo@elte.hu>

Alan Cox reported that lockdep runs out of its stack-trace entries
with certain configs:

BUG: MAX_STACK_TRACE_ENTRIES too low

This happens because there are 1024 hash buckets, each with a
separate lock. Lockdep puts each lock into a separate lock class and
tracks them independently.

But in reality we never take more than one of the buckets, so they
really belong into a single lock-class. Annotate the has bucket lock
init accordingly.

[ Impact: reduce the lockdep footprint of dma-debug ]

Reported-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
lib/dma-debug.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index a9b6b5c..c9187fe 100644
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -716,7 +716,7 @@ void dma_debug_init(u32 num_entries)

for (i = 0; i < HASH_SIZE; ++i) {
INIT_LIST_HEAD(&dma_entry_hash[i].list);
- dma_entry_hash[i].lock = SPIN_LOCK_UNLOCKED;
+ spin_lock_init(&dma_entry_hash[i].lock);
}

if (dma_debug_fs_init() != 0) {
--
1.6.3.3



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